How to get from multiple ChannelId's to one ChannelId

[Sacha Schlegel <sacha_oasis@schlegel.li>]

Hi everyone

From my understanding there are two necessary processes how to get from
two CPP's to a final CPA.

1. process: CPA composition
2. process: CPA negotiation

The output of the CPA composition process is a new NDD_for-cpa-template
plus a new CPA template.

Question is: how to get from multiple ChannelId's to one ChannelId.

What is the difference between enumerations laid out in the CPP instance
Document (eg certificates) and enumerations laid out in the cppa schema
itself (from The Automated Negotiation of CPA (ANCPA) Spec in 10.1
(Enumerations))?

I think the example of multiple ChannelId's in ThisPartyActionBinding
goes into the cpp instance docuemnt enumeration problem...

Assuming that the party who runs the CPA composition does not modify the
other parties CPP and each CPP has multiple ChannelId's per CPP.

Example:

<CPP id=1>
  ...  
 <ThisPartyActionBinding>
   ...
   <ChannelID id=1>x</ChannelId>
   <ChannelID id=2>y</ChannelId>
   <ChannelID id=3>z</ChannelId>
 <ThisPartyActionBinding>
  ..
</CPP>


<CPP id=2>
  ...  
 <ThisPartyActionBinding>
   ...
   <ChannelID id=5>a</ChannelId>
   <ChannelID id=6>b</ChannelId>
   <ChannelID id=7>c</ChannelId>
 <ThisPartyActionBinding>
  ..
</CPP>

In this example there are 3 ChannelIds per ThisPartyActionBinding in
each CPP

The CPA composition would have to check all combinations (3x3 = 9) and,
from my understanding, list conflicts as negotiatable items in the NDD.
There must be a way to indicate for which combination a conflict exists:

combination-x-a: conflict in transport protocol (via XPath expression to
transport protocol)
combination-x-b: conflict in transport protocol version

What I want to say is that once the CPA negotiation chooses
combination-y-b as the one which will go into the CPA (however this is
done) all conflicts of  the other combinations can be removed.

The more I think, the more problems I discover (eg in connection with
BusinessTransactionCharacteristics) and probably should reread the ANCPA
spec.

It might be easier if the CPA composition tool leaves all ChannelId's in
the CPA template (even if its basically a not ready CPA yet).

An argument against could be that, in the case of the ChannelId example,
the CPA composition tool might remove all ChannelIds and use (one or
two???) Reference  elements in the NDD with a choice for CPP with id=1
of x,y, or z and one Reference element in the NDD with a choice for CPP
with id=2 of a,b, or c. This might be valid as the value of the
ChannelId element _references_ another element.

If the multiple elements on the other hand have children then, of
course, it cannot be removed as all information would get lost, unless,
all elements with their children will go into the NDD and the Reference
element has elements with children as options. The Reference element in
the NDD might have to be checked again...

Sometimes I think the content of the NDD has to be negotiate first (or
agreed upon) and then negotiated over the elements described in the NDD
...

Hope this makes some sense.

Kind regards

Sacha Schlegel


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